1. Field of the invention
The present invention relates to a wrist support device and, in particular, to a device which is used to support the base of a user's hand and the bones of the wrist when performing repetitive motions, such as typing or data entry on a computer keyboard, thereby preventing the development of repetitive stress disorders, such as carpal tunnel syndrome.
2. Prior art
Due to the widespread use of computers and other word processing equipment, the number of persons using keyboards to enter data and perform other tasks which involve repetitive movements of the fingers and hands has greatly increased. With these increases in the number of users has also come an increased understanding of the risks which repetitive stresses raise regarding the health of those using such devices. The most common are repetitive stress disorders such as carpal tunnel syndrome--a disorder which can lead to debilitating pain in the wrists of those who use typewriters, keyboards and other data entry devices.
Carpal tunnel syndrome is believed to develop as the hands and wrists of the user are held in an unnatural position during repetitive tasks performed over a prolonged period of time which place stress on the wrist. The most common scenario is that of a secretary or data entry person who spends long hours entering information into a computer via the computer's keyboard.
To avoid the pain suffered by employees and the loss of valuable employee time which accompany repetitive stress disorders, several devices have been created to reduce the risk of persons getting carpal tunnel syndrome. One common device is a wrist support brace which is worn about the wrist and lower part of the user's hand. The wrist support brace has braces formed therein to prevent the wrist from bending and causing stress on the damaged or inflamed carpal tunnel within the wrist. However, such devices are generally not favored because they are inconvenient, time consuming and awkward to put on and to remove by oneself. Additionally, the braces restrict all movement of the wrist, may put pressure on the inflamed or damaged wrist, and are generally unsightly. Thus, the wrist support braces are generally only worn by those who are already suffering from wrist pain due to repetitive stress disorders.
Another device which has gained significant popularity is an elongate pad. The elongate pad is typically made of neoprene or some other somewhat pliable material and is positioned in front of the keyboard so that the user's hands or wrists may rest on the pad while typing. Unfortunately, the pad does not move with the user's hands or wrists. As a user moves his or her hands, the material of the elongate pad tends to irritate the skin on the bottom of the wrist as the two rub against one another. Those who work for prolonged hours using such a device often suffer pronounced irritation on the underside of the hand and wrist.
An additional concern with the elongate pads is that they can actually cause stress on the wrist. If the bony portion of the user's wrist (i.e. the portion including the pisiform) is placed above the pad, the lack of support under the other wrist bones, especially those near the base of the thumb, causes the user's hand/wrist to rotate into a generally horizontal position. The natural position for a persons hand/wrist is an incline of between 10 and 30 degrees. As the wrist and the user's hand are held in a horizontal position, the elbow is forced to rotate outwardly and additional stress is placed on the wrist, as gravity continually pulls down on the elbow.
To overcome these concerns, many users place the elongate pad directly below the soft tissue between the bones of the wrist and the radius and ulna, minimizing the amount of rotation. However, in such a position, the weight of the arms and hands places pressure on the soft tissues and on the tendons of the wrist. This, in turn, raises concerns of repetitive stress disorders.
While other suggestions have been made regarding the attachment of wrist supports to a user's arm, see e.g. U.S. Pat. No. 1,510,877, such devices are generally not desirable because they move with the user's hands when lifted away from the keyboard. Thus, for example, if the hands of a person periodically leave the keyboard to pick up or move materials, the support devices go with the user's hands, potentially interfering with the other task. Additionally, having a support device strapped to one's wrist is generally unattractive and restricts natural breathing and air circulation at the skin. Such unnatural conditions can be problematic for people with sensitive skin. Furthermore, if the strap is securely placed around the wrist, additional pressure would be applied to the carpel tunnel and actually increase the risk of repetitive stress disorders, rather than helping reduce the risk of the same.
Co-pending application Ser. No. 08/609,675, filed Mar. 1, 1996, provides a significant improvement over prior art devices by providing a wrist support means with an upper surface defining a concave portion configured to engage the pisiform of a user, a biasing means circumscribing the concave portion for biasing the wrist to a laterally inclined orientation and nesting the wrist into the approximate center of the upper surface, and a gliding means for movement of the wrist support means along a planar surface. Thus, the wrist of the user is encouraged into a natural orientation and moves planarly with the wrist of the user.
However, there is still a need for a device which supports the wrist of the user in a more cushioned manner. In addition, there is a need for such a device that will facilitate the release of the user's wrist from the surface of the device because natural adhesion occurs from prolonged contact. In addition, there is a need for a device capable of use with both low and high friction surfaces, including desks and mouse pads. In addition, there is a need for a device that provides different stages of cushion, or various levels of cushioning as engaged by the wrist. Furthermore, there is a need for a device that allows the wrist and hand to pivot or rotate a small amount for added comfort.